中文摘要：

股票市场平均市盈率太高意味着存在股价泡沫，发生金融危机的可能性增大。为了分析证券交易税对股市泡沫是否有抑制作用，选取出于抑制股市泡沫目的而对证券交易税税率进行的两次调整，采用上海证券市场A股的数据，通过描述性统计和单因素方差分析比较调整前后的市盈率，发现证券交易税对抑制股市泡沫有显著影响，这种影响在短期内特别明显。政府可以根据市盈率水平来调整证券交易税税率，使投资者对证券交易税政策形成明确的预期，起到减少过度投机的作用。

英文摘要：

The high average price earning ratio implies the existence of the stock price bobbles in stock market and increases possibility for financial crisis. In order to analyze whether securities transaction tax has the inhibitory effect on the stock market bubbles, we selected the two adjustments of securities transaction tax for inhibiting stock bubbles, used the data of Shanghai A- share and compared PE ratios before and after adjustment by descriptive statistics and single factor variance analysis, the results show that securities transaction tax has obvious impact on inhibiting stock bubbles and that this kind of impact is significant in short time. Government can adjust the rate of securities transaction tax according to PE ratio in order to make the investors have clear expectation for seeurities transaction tax policy and to reduce excessive speculation.